function [x_next, q_next] = nhmm(x, q, u, k, a, b)
% 计算 NHMM 模型单步迭代的情况
%   x_{n+1} = u sin(x) (1 - sin(x)) + k (a + b q^2) x
%   q_{n+1} = q + 0.1 x
    x_next = u * sin(x) * (1 - sin(x)) + k*(a + b*q^2)*x;
    q_next = q + 0.1*x;
end
